Thursday, September 30, 2010

Contador's story seems to hold up scientifically

Big news in the cycling world today is that Alberto Contador has tested positive for a banned substance known as Clenbuterol. Now I love the Tour de France and I watch it every year and I look forward to watching. As a cycling fan I am as pissed off as everyone that this sport is so tainted by drug use. It is so difficult to judge whether a performance has been effected by PEDs or not and most people now assume that they are all doing.

Now I also want to get straight that I am not necessarily a Contador fan and I am not looking for a reason to find him either guilty or innocent. I actually think he is an arrogant, smug guy and if I was to state what I think of him personally I would have to say that I would rather root for someone else (like my man Cadel Evans, go Aussie!). There is no denying the man's achievements in big races and until he is proven otherwise as a fan you have to have faith that he is clean So when the report came out that he had tested positive for Clenbuterol I was very disappointed. I was so hoping that he was clean but now this is all over the news.

As a scientist I wanted to dig a little deeper into the facts about Contador's case. In particular he made a claim that the levels of Clenbuterol found were due to a steak that he had eaten the night before. My immediate reaction was whether this was even possible. Well apparently it is possible and I decided to take a more scientific approach to see whether his claims could be true.

Clenbuterol is an actual drug used to treat asthma but it also has an effect of decreasing body fat. This is the reason that athletes and particularly cyclists may want to take it as it will produce leaner muscle (also popular with bodybuilders apparently). It is also on the UCI list of banned substances.

First to Contador's story. He claims the levels that were detected were due to consumption of a piece of steak that he ate the night before. Firstly levels of Clenbuterol have been detected before in humans after eating meat contaminated with Clenbuterol. Farmers illegally feed their livestock Clebuterol to produce a leaner stock. Some scientific stuff, the bioavailbility of Clenbuterol is around 80% therefore if it was present in the meat it could be ingested and adsorbed into the body. Secondly studies have shown that cooking meat does not cause it to significantly decompose. In summary Contador's story is potentially true, not so unrealistic at least.

Let's turn to the possibility that he knew (or someone knew) that this could be a cover story in case they got busted and he was actually taking it beforehand. At the Tour de France riders are tested just before the race, the winners of every stage, the yellow jersey and 6-8 riders are tested randomly and are tested immediately after each stage. Contador took at the yellow jersey at stage 15 on July 19. He was tested again on July 21 and it was this test which produced the positive result. Admittedly the levels tested were very low (50 picograms/mL) which are 400 times below the recommended detection limit. Now I don't know if all the other samples were also tested to this low limit. Let's say that the 50 picograms/mL came from him taking Clenbuterol after some time before the Tour De France. Based on the known half life of Clenbuterol if he was tested on Day 1 of the race the levels in his body would have been about 800 ng/mL (assuming the natural elimination in the body). This is way above the level of 20 nanograms/mL that they are usually testing for. Therefore it seems very unlikely that a detection of 50 picograms/mL on July 21 is matched to a clean test at the start of the race.

There are obviously a couple of holes here like : What about masking agents and what effect does a lower dose have? I couldn't find any info on these topics so I can't say. But on the surface it seems as though Contador's story hold up scientifically.

Therefore he either has some scientists helping to create his story or he is telling the truth about the contaminated meat. Maybe we will find out. Maybe not.